tournaments

to learn the tarrasch just look at a few games of the GM's online and play only blacks moves to see what sort of pawn structures they end up with and how the manouver their pieces to support the pawns and the space in front of them.

then play through the games in full and see what sort of endgames they end up with and the ideas they use to win them.

no matter what your opponent does you will be able to come up with a plan to attack the weaknesses they leave in the centre.

attack, but have the patience to take 60 moves to win if that is as long as it takes.